Parts for your 2008 Subaru Forester-Drive belt tensioner

2008 Subaru Forester drive belt tensioner — what’s actually fitted

For the 2008 Subaru Forester (SG series, EJ25 engines), a conventional spring‑loaded serpentine drive belt tensioner isn’t used. Instead, the vehicle runs two separate accessory belts that are tensioned manually via adjustable idler/adjuster hardware on the alternator/power steering and on the A/C bracket. This layout is confirmed by the Subaru Factory Service Manual for the 2008 Forester (Drive Belt section), plus the Gates and Dayco application catalogues for AU/NZ, which list belts with manual adjustment and no automatic tensioner assembly for this model year. Many parts listings that show a “drive belt tensioner” for Forester apply to later FB‑engine models (2011‑on) with a single serpentine belt, not this 2008 EJ‑engine car.

Why no spring tensioner on this one? Subaru’s EJ accessory system of the era was designed around simplicity and separate belt runs. The alternator/PS and A/C belts each use an idler and a long adjuster screw to set tension. It’s a robust, low‑cost setup that works fine as long as the belts are checked and adjusted during routine servicing. Subaru’s own procedures describe loosening the lock bolts, turning the adjuster to spec, and re‑torquing—no spring‑loaded unit involved. Dayco AU/NZ and Gates technical data echo this, noting manual tensioning on 2008 Forester EJ applications.

What should be serviced instead of a “tensioner” unit? Simple stuff:

• Inspect both accessory belts for cracks, glazing, fraying, or chirps/squeals on start‑up.
• Check the idler pulleys and alternator/A/C adjuster mechanisms for smooth movement and bearing noise.
• Set belt tension using the adjuster screw and lock bolts, following workshop specs and using a belt tension gauge if available.
• Look for belt dust, misalignment, or corrosion on the adjuster studs that can seize over time.

If you’re shopping parts, don’t confuse the accessory drive with the timing belt system—the EJ timing belt does have its own hydraulic tensioner, but that’s unrelated to the external accessory belts. For a 2008 Forester, if a listing shows a spring‑loaded serpentine belt tensioner for the accessories, it’s not relevant to this model year and engine family.

Popular questions

Does a 2008 Subaru Forester have a drive belt tensioner?
No automatic spring‑loaded tensioner is fitted. The car uses two accessory belts that are tensioned manually via adjuster screws and idler brackets on the alternator/PS and A/C assemblies. This matches the Subaru Factory Service Manual and AU/NZ Gates and Dayco catalogues for the 2008 EJ25 Forester.

How is belt tension adjusted on a 2008 Forester?
Under the bonnet, the lock bolts on the relevant bracket are loosened, the long adjuster screw is turned to set belt tension to spec, then everything is re‑tightened. A belt tension gauge is ideal